INDUCTION OF FOS-LIKE IMMUNOREACTIVITY IN THE LOWER BRAIN-STEM AND THE SPINAL-CORD OF THE RAT BY INTRAPERITONEAL ADMINISTRATION OF AN ENDOGENOUS SATIETY SUBSTANCE, 2-BUTEN-4-OLIDE

Induction of Fos in neurons by intraperitoneal injection of 2-buten-4- olide (2-B4O), an endogenous satiety substance, was studied immunohist ochemically in the brainstem and spinal cord of the rat. Rats injected intraperitoneally with 2-B4O (100 mg/kg) were allowed to survive for 2 h before perfusion. Fos-like immunoreactivity was observed in neuron s of the intermediolateral nucleus, ventral reticular formation, later al reticular nucleus, nucleus of the solitary tract, locus coeruleus, lateral parabrachial nucleus and dorsal raphe nucleus, as well as in t yrosine hydroxylase-immunoreactive neurons of the cell groups A1, A2, A5, A6, A7, C1, C2 and C3. (C) 1997 Elsevier Science Ireland Ltd.